1. Field of the Invention
This invention relates to a hydraulic circuit including a cylinder for moving a heavy article or counterweight from one position to another position, and more particularly a hydraulic circuit adapted for smoothly moving a heavy article without shock.
2. Description of the Prior Art
Referring to FIGS. 1 and 2, which show the conventional pipe layer bulldozer, the bulldozer has a crane b at one side of the body a thereof and a counterweight c provided through a quadric link d at the other side of the body a. A cylinder (e) is provided for moving the counterweight c between the first position as shown in FIG. 1 extending from the body a and the second position as shown in FIG. 2 drawn to the body a. This pipe layer bulldozer has a disadvantage that since a large force is necessary at the initial part of the movement of the counterweight c by the cylinder e from the first to the second positions and a small force is sufficient at the end of the movement thereof, if the cylinder e is quickly moved in order to accelerate the moving speed of the counterweight c, the counterweight c stops with shock at the end of its stroke with the result that the shock stress takes place at the pivotal portions of the quadric link d and cylinder e causing the pivotal portions to be damaged.